Linux Driver For Arm China's Zhouyi AI Accelerator Proposed, But Lacks Open User-Space

The Zhouyi AI accelerator was developed by Arm China and is found in some SoCs so far. An open-source Linux kernel driver is being worked on for it but unfortunately for now at least any mainline ambitions are immediately stalled over the lack of an open-source user-space/client.

A Baidu engineer posted a set of patches implementing the Zhouyi AI accelerator support in a new "zynpu" driver for the kernel. The more than five thousand lines of code provide this initial support. The Zhouyi AI accelerator is found in some Arm SoCs like the Allwinner R329.

This driver in its initial form supports both the ZHOUYI Z1 and ZHOUYI Z2. This initial Linux kernel driver, which is seeking for inclusion into the kernel's "staging" area until in better shape, can be found on the kernel mailing list.

But any mainlining effort for now is immediately stalled as the Zhouyi AI accelerator lacks an open-source user-space driver/SDK. Arm China is only distributing the user-space components as binary blobs and thus until there is an official open-source user or reverse-engineered open implementation, this driver won't be accepted to the mainline kernel.

Even the developer involved in writing this kernel driver doesn't appear to have the user-space sources but is going to be left to reverse-engineer it. Cai Huoqing noted, "The usermode code is close, I just got an library... it only works with a closed source usermode driver, so need to reverse the libraries, and implement it, then open source
the usermode driver."